The present invention relates generally to an inspection device and method, and more particularly to a device and method for inspecting a granular product.
In the production granular products including powders, there is a desire to inspect the product to determine various qualities of the product, such as size, shape and color characteristics of the granules and the presence and quantity of any impurities, as well as characteristics of those impurities. Other qualities that may be desired to be determined include flow characteristics of the granules and granule surface characteristics.
Granular products include powders as well as coarser mixtures of granules. Examples of granular products that may be inspected include pharmaceutical products, food products (rice, grain, cereals, flour, confections, sugar, etc.), cosmetic products, aggregates, ores, plastics and other petrochemical products, and many more.
Various methods and devices for performing such an analysis have been employed for these purposes which may employ laser diffraction, spectroscopy, and various forms of visual image analysis.
A problem in inspecting granular products, particularly when image analysis is employed, is in presenting the product to the image capturing device so as obtain an optimal image of the product. It is desired, for example, to have a controllable quantity of the product within the image area so that an image can be made of the desired quantity. In addition, it is desired to have a controlled and uniform spread of the material so that the image represents a fair sampling of the product. It is also desirable to be able to control a thickness of the spread of material in the image area, depending on what type of characteristics are being determined. In some cases a single layer of granules is required to achieve imaging of substantially all of the product, for example, if it is necessary to show the complete absence of a particular defect. In other cases, it may be desired to have less than a single layer, i.e., with space between the individual granules for improved inspection of individual granule characteristics. In still other cases, a thicker layer of granules may be desired when a sampling of the product characteristics is sufficient. It is also desired to present the granules to an image capturing device in an even manner, so that the granules being imaged are on a single plane and/or at a given distance from the imaging device.